WASHINGTON (AP) — A senior U.S. defense official says the Pentagon has delayed an intercontinental ballistic missile test for next week at an Air Force base in California amid mounting tensions with North Korea.

The official says Defense Secretary Chuck Hagel delayed the long-planned Minuteman 3 test because of concerns the launch could be misinterpreted and exacerbate the current crisis.

The official was not authorized to speak publicly and requested anonymity.

North Korea’s military has warned that it was authorized to attack the U.S. using “smaller, lighter and diversified” nuclear weapons.

South Korean officials say the North moved at least one missile with “considerable range” to its east coast, suggesting a launch could be imminent.

U.S. and South Korean annual military exercises have been ongoing, with warships and bombers in the region.